Cop (1988)

Cop is a 1988 crime thriller starring James Woods as Lloyd Hopkins, an LAPD detective who lives on the edge and goes to extreme lengths in his pursuit of a decades-old serial killer. This film was adapted from the novel "Blood on the Moon" that was written by James Ellroy (the author of L.A. Confidential) and the cast included Charles Durning, Charles Haid, and Lesley Ann Warren.

Shotguns

Ithaca 37

Det. Dutch Peltz (Charles Durning) uses a 12-gauge Ithaca 37 with a full stock during a confrontation at a traffic stop. An Ithaca with a shortened stock is seen in a gun rack at the home of Sheriff's Deputy Delbert 'Whitey' Haines (Charles Haid). Both Haines and Hopkins are seen using it.